WO2022228427A1 - Method for preparing glass material with high compactness, glass material, and use - Google Patents

Abstract

Disclosed in the present invention is a method for preparing a glass material with high compactness, comprising the following steps: 1) obtaining a glass substrate; and 2) carrying out heat treatment on the glass substrate obtained in step 1) before carrying out first chemical strengthening on same, so as to obtain a glass material with high compactness, wherein the temperature Theat of the heat treatment and the strain point Tstrain of the glass material are controlled according to the following: Theat＝(Tstrain-70 ℃) to (Tstrain+20 ℃), and the strain point Tstrain is less than or equal to 550 ℃. By means of the method for preparing a glass material with high compactness in the present invention, the network structure of glass can be more complete, the intrinsic strength of the glass can be improved, and the glass has a better anti-falling performance after being subjected to subsequent ion exchange treatment.

Description

A kind of preparation method of glass material with high density, glass material and application

This application claims the priority of the Chinese patent application filed on April 30, 2021 with the application number of 202110485537 . The contents are incorporated herein by reference.

technical field

The invention relates to the technical field of glass products, in particular to a method for preparing a glass material with high density, a glass material and applications.

Background technique

Ultra-thin glass, typically between 0.1mm and 1.2mm thick. Of course, there are also some models that have a thickness of less than 0.1 mm; among them, ultra-thin glass with a thickness of between 0.2 mm and 1 mm can be bent, while those with a thickness of less than 0.2 mm can be folded. Taking into account the scope of application, yield and cost, ultra-thin glass with a thickness of 0.1mm to 0.5mm has a larger share of the market.

Ultra-thin glass is very thin, which also reduces the weight of the ultra-thin glass product itself, which can reduce the weight of the final product in application, thereby bringing about a weight advantage. The "thinness" of ultra-thin glass also brings better optical quality to ultra-thin glass products. For example, in the smartphone industry, the application of ultra-thin glass can also improve the speed and accuracy of fingerprint recognition under the screen. The strengthening of ultra-thin glass is achieved by chemical strengthening, specifically, the large alkali metal ions in the salt bath, such as potassium ions and sodium ions, exchange sodium ions and lithium ions inside the glass at high temperature, and finally due to the volume difference effect of exchange ions , compressive stress is generated inside the glass, making it more difficult for the micro-cracks caused by the collision to expand and grow, increasing the strength of the glass.

At present, the ultra-thin glass used for glass cover is basically produced by the overflow method and the float method. The glass material obtained after production is annealed and then chemically strengthened to improve the stress performance of the glass material. However, in actual production, it is found that the effect of chemical strengthening on the stress performance improvement of glass materials is very limited. When improving the ion exchange process, the prior art focuses on increasing the ion exchange capacity of the glass material, because the smaller the ion exchange capacity, the smaller the CT-LD value of the strengthened glass material, and the worse the stress performance obtained by the glass material. . Although increasing the ion exchange amount can improve the CT-LD of the glass material to a certain extent, the higher the ion exchange amount is, the better, and the excessively high ion exchange amount will have a negative impact on the CT-LD of the glass material and damage the glass material. Stress properties obtained after chemical strengthening. At the same time, the increase of ion exchange will bring more negative effects. The increase of the ion exchange amount will cause more alkali metal ions in the glass material to enter the salt bath for chemical strengthening, causing poisoning in the salt bath, which will not only affect the subsequent ion exchange effect of the glass material in the salt bath, It will also shorten the service life of the salt bath.

Therefore, how to reconcile the contradictory relationship between the ion exchange amount of the glass sample during the chemical strengthening process and the CT-LD obtained by the glass sample is an urgent problem to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

In view of the above deficiencies in the prior art, the purpose of the present invention is to provide a method for preparing a glass material with high density, so as to solve the problem that the prior art is difficult to balance the ion exchange capacity of the glass sample during the chemical strengthening process and the final acquisition of the glass sample. There are contradictory problems in CT-LD.

The present invention also provides a glass material with high density.

The invention also provides the application of a glass material with high density.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

A first aspect of the present invention provides a method for preparing a glass material with high density, comprising the following steps:

1) obtaining a glass substrate containing an alkali metal, wherein the alkali metal at least contains lithium element;

2) heat-treating the glass substrate obtained in step 1) before its first chemical strengthening to obtain a high-density glass material;

Wherein, the _heat treatment temperature T and the strain point T of the glass material _{should be} controlled as follows:

T _heat =(T _{should be} -70℃)～(T _{should be} +20℃); the strain point T _{should be} ≤550℃.

The second aspect of the present invention provides a glass material with high density, the glass material with high density is obtained by the method for preparing a glass material with high density described in the first aspect of the present invention, and after the heat treatment The CT-LD _max of the glass material is at least 40000MPa/mm or more.

A third aspect of the present invention provides a method for preparing chemically strengthened glass, comprising: subjecting the high-density glass material described in the second aspect of the present invention to a nitrate bath containing sodium ions or sodium ions and potassium ions for primary ionization exchange or secondary ion exchange.

The fourth aspect of the present invention provides a chemically strengthened glass prepared according to the preparation method of the third aspect of the present invention.

A fifth aspect of the present invention provides an electronic terminal as a consumer product, comprising:

a housing including a front surface, a rear surface and a side surface;

and an electronic assembly located partially within the housing, the electronic assembly including a display located at or adjacent to a front surface of the housing;

the front surface or/and the rear surface or/and the side surface comprises the chemically strengthened glass according to the fourth aspect of the present invention;

Also included is a cover article overlaid at the front surface of the housing or on the display, the cover article comprising a high-density glass material as described in the present invention;

The electronic terminal as a consumer product includes a mobile phone, a tablet computer, or other electronic terminals.

Compared with the prior art, the present invention has the following beneficial effects:

1. In the present invention, the glass material is heat treated at a certain temperature, and the glass material is subjected to a Raman test before and after the heat treatment, and then a chemical strengthening treatment is performed. Excellent drop resistance. After analyzing the Raman test spectrum of this glass, it was found that the Raman test spectrum of the heat-treated glass material changed greatly from the Raman test spectrum before heat treatment. The ratio M of the peak area S ₉₈₀ of the characteristic frequency peak obtained at the characteristic frequency 980 on the Raman test spectrum of the latter glass material and the peak area S ₁₀₆₀ of the characteristic frequency peak obtained at the characteristic frequency 1060, obtained at the characteristic frequency 480 The peak intensity N value of the characteristic frequency peak, both of which have a certain degree of decrease compared with before heat treatment, the decrease of M value means that the peak area of the characteristic frequency peak obtained at the characteristic frequency 1060 of some glass materials S ₁₀₆₀ after heat treatment There is an increase, which also means that the network structure of these glass materials has changed to a certain extent after heat treatment. The six-membered ring layered structure in the network structure has increased significantly, and the non-bridging oxygen bond in the six-membered ring layered structure. The number has increased significantly, and the decrease of N value indicates that the number of bridge oxygen bonds in the glass six-membered ring layered structure has decreased. The changes of the two indicate that the network structure of the glass material tends to be more stable after heat treatment. Six-membered ring layered structure, and this structure becomes more complete after the heat treatment described in the present invention, so that the heat-treated glass material has higher density, and the intrinsic strength of the glass material is improved, so that the After the subsequent ion exchange treatment, the anti-drop performance is better.

2. The glass materials with high compactness described in the present invention are not obtained through simple preheating treatment. After studying the heat treatment process of these glass materials, it is found that controlling the temperature is the key. There is a certain relationship between the temperature and the strain point of the glass material itself. Through the relationship between the heat treatment temperature and the strain point of the glass material according to the present invention, the temperature of the heat treatment can be precisely regulated, so that the glass material after heat treatment has higher The density of the glass material is more complete.

3. The glass material treated by the heat treatment process of the present invention also exhibits more excellent performance during chemical ion exchange. Under the same chemical strengthening conditions, the high-density glass material of the present invention can be The lower sodium ion exchange amount can obtain a higher CT-LD _max than the glass material that has not undergone the heat treatment described in the present invention, so that the ion exchange amount of the heat-treated glass material during the entire ion exchange process is due to the chemical strengthening of the glass. Smaller, the change of size and profile is in a stable and controllable state, and the final chemically strengthened glass material has better anti-drop performance.

Description of drawings

FIG. 1 is a Raman test spectrum of the glass materials of Examples 2-7 without heat treatment.

FIG. 2 is a Raman test spectrum of the glass material after heat treatment in Examples 2-8.

FIG. 3 is a Raman test spectrum of the glass materials of Examples 4-7 without heat treatment.

FIG. 4 is a Raman test spectrum of the glass material after heat treatment in Examples 4-8.

In the figure: 1 represents the 980Hz characteristic frequency peak on the Raman test spectrum, 2 represents the 1060Hz characteristic frequency peak on the Raman test spectrum.

Detailed ways

The present invention will be described in further detail below with reference to the embodiments and accompanying drawings.

1. The relevant special names and relevant measurement methods involved in the present invention are explained as follows

Glass substrate: It is a glass substrate material that has not been strengthened.

Tempered glass: It is chemically strengthened glass treated by high temperature ion exchange process. In the high-temperature salt bath, the alkali metal ions with large ionic radius replace the alkali metal ions with small ionic radius in the glass, resulting in the exchange ion volume difference, which produces a high-to-low compressive stress in the surface layer of the precursor glass, which hinders and retards the glass. The expansion of microcracks achieves the purpose of improving the mechanical strength of the glass.

Surface compressive stress CS: After the glass is chemically strengthened, alkali metal ions with a smaller surface radius are replaced by alkali metal ions with a larger radius. Due to the crowding effect of alkali metal ions with a larger radius, compressive stress is generated on the glass surface.

Depth of compressive stress layer DOL-0: refers to the depth position within the strengthened glass at which the compressive stress generated from the strengthening process reaches zero.

Tensile stress linear density CT-LD: According to the SLP stress instrument test, the ratio of the integral of the tensile stress to the thickness of the glass under its thickness section is obtained. In chemically strengthened glass, the compressive stress and tensile stress are in a balanced relationship, and the SLP-1000 stress meter is more accurate in testing the tensile stress area of the glass. Therefore, the tensile stress integral and the thickness ratio are used to characterize the stress contained in the unit thickness of the glass. Used to characterize the degree of stress in chemically strengthened glass.

CT-LD _max : With the extension of the strengthening time, the tensile stress linear density CT-LD presents a parabolic form, and there is a highest point, which is called CT-LD _max .

Strain point of glass material: The strain point of glass is the temperature equivalent to a viscosity of 10 ^13.6 Pa.s, so that the stress can be eliminated within a few hours.

CT-CV: Characterizes the maximum value of the tensile stress region in the stress obtained by the SLP stress instrument test, referred to as the maximum tensile stress.

Raman test: that is, Raman spectroscopic analysis, which is a kind of scattering spectrum. Raman spectroscopy is an analysis method based on the Raman scattering effect, which analyzes the scattering spectrum different from the incident light frequency to obtain information on molecular vibration and rotation, and is applied to the study of molecular structure. The invention adopts the German Bruker VERTEX80 Fourier infrared spectrometer to conduct Raman spectrum analysis on the glass material.

Drop test of the whole machine: a method of testing the strength of tempered glass, attaching tempered glass sheets to samples of electronic devices such as mobile phones, and falling from a high place freely, recording the height at which the glass is broken, this height value can reflect the glass The strength of this test method is called the drop test of the whole machine.

Chemical strengthening limit experiment: It refers to the relationship between the time and stress of the sodium-lithium ion exchange of lithium-aluminum-silicon chemically strengthened glass. Generally, the lithium aluminum silicate glass sheet is put into pure sodium nitrate, and ion exchange is carried out at 430 °C. Take out the glass at regular intervals (15min, 30min, or 60min), use SLP1000 or SLP2000 stress meter to test and record the stress. After the test is completed, put it in a salt bath to continue strengthening until the stress CT-LD shows a significant downward trend. Stop the experiment.

In the present invention, FSM6000 and SLP1000 produced by Orihara Company can measure the surface high pressure stress area and deep low pressure stress area respectively, and use PMC software to fit the stress curve to obtain the corresponding test results. Of course, other stress testers that can measure the surface high pressure stress region and the deep low pressure stress region can also be used. The density was measured by the Archimedes drainage method, and the test instrument was Shimadzu Density Tester AUY120.

2. A kind of preparation method of glass material with high density

1) obtaining a glass substrate containing an alkali metal, wherein the alkali metal at least contains lithium element;

2) heat-treating the glass substrate obtained in step 1) before its first chemical strengthening to obtain a high-density glass material;

Among them, the heat treatment temperature T _heat and the strain point T of the glass material _should have the following relationship:

T _heat =(T _{should be} -70℃)～(T _{should be} +20℃); the strain point T _{should be} ≤550℃.

The preparation method of the present invention is aimed at glass substrates containing alkali metals, especially glass substrates containing lithium element, because in the process of ion exchange of glass, lithium element is one of the important elements in ion exchange, and glass will K ⁺ -Na ⁺ , Na ⁺ -Li ⁺ binary ion exchange is carried out in steps or simultaneously, so that the glass can obtain a composite compressive stress layer after ion exchange. The network structure of the glass itself also affects the stress effect obtained after ion exchange. After the heat treatment according to the present invention, the structure of the glass substrate changes obviously, its network structure becomes denser, and the density of the glass material is obviously improved after the heat treatment according to the present invention. When the density after heat treatment is increased by at least 0.15% or more compared to before heat treatment, such a glass can be regarded as a glass material with high density.

In one or more embodiments, the glass substrate obtained in step 1) is preheated at 200°C to 350°C before step 2). The preheating treatment performed at this time is a conventional heat treatment. The purpose of preheating is to dry the moisture of the glass, and to heat the glass in advance to generate a certain preparatory temperature, which is generally only 200°C to 350°C. The maximum time is 30min, so that there is a thermal transition before the glass is subjected to the subsequent processing process, and there will not be too much temperature change, which will cause the glass to break. This preheating treatment will not affect the structure of the glass, and there is no significant change in the density and stress of the glass after heat treatment. When using the preparation method of the present invention, this preheating process can be omitted. The preheating temperature includes 200°C～350°C and all ranges and sub-ranges therebetween, such as 200°C～230°C, 200°C～240°C, 250°C～300°C, 240°C～290°C, 260°C～310°C, 270℃～320℃, 280℃～330℃, 290℃～340℃, 220℃～300℃, 250℃～350℃, 300℃～350℃, 310℃～350℃, etc.

In one or more embodiments, the strain point T of the glass substrate _{should be} closely related to the composition of the glass substrate itself. If the density of the glass substrate is to be changed, the _heat treatment temperature T should be based on the strain point of the glass material. T _should be adjusted. The heat treatment temperature should strictly satisfy the relationship between it and the strain point. If the heat treatment temperature is too low or too high, it will adversely affect the performance of the glass material. If the heat treatment temperature is too low, the structure of the glass material will not change, and it will not be able to improve its density. If the heat treatment temperature is too high, the network structure of the glass material will be destroyed, but the density of the glass material will decrease, which will greatly affect the final chemical strengthening effect of the glass material, making the chemically strengthened glass material. Decrease in magnitude. Heat treatment temperature T _heat includes 300°C to 570°C and all ranges and sub-ranges therebetween, such as 300°C to 400°C, 320°C to 460°C, 320°C to 470°C, 310°C to 450°C, 380°C to 500°C , 350℃～520℃, 360℃～520℃, 390℃～420℃, 350℃～480℃, 320℃～420℃, 320℃～510℃, 450℃～520℃, 450℃～510℃, 450℃ ℃～530℃, 450℃～550℃, 450℃～500℃, etc.

In one or more embodiments, the time of the heat treatment in step 2) is 1 h to 12 h. When heat treating the obtained glass substrate, the _heat treatment temperature T _should be adjusted according to the strain point T of the glass substrate. Similarly, attention should be paid to the heat treatment time. Too short heat treatment time will cause structural changes of the glass substrate. The depth of the glass substrate is not enough, that is, the internal structure of the glass substrate has not had time to undergo deeper changes, and the heat treatment process will end, which will lead to little or no change in the density of the resulting glass substrate, and ultimately the density of the glass substrate will change. Very limited, or even no change at all; and excessive heat treatment time will damage the network structure of the glass substrate, disintegrate the originally formed dense structure, and ultimately lead to a significant reduction in the stress properties of the glass substrate after chemical strengthening. , At the same time, too long heat treatment time will increase energy consumption and increase production cost, which is not worth the loss. Therefore, the time of the heat treatment in step 2) is 1h-12h and all the ranges and sub-ranges therebetween, such as 2h-6h, 2h-5h, 2h-4h, 2h-3h, 4h-10h, 5h-6h, 3h～6h, 1h～6h, 6h～7h, 6h～8h, 6h～9h, 6h～10h, 7h～8h, 7h～9h, 8h～9h, 8h～10h, 9h～12h, 7h～11h, preferably 2h～4h, including 2.1h～3h, 2.2h～3.0h, 2.3h～3.0h, 2.4h～3.0h, 2.5h～3.0h, 2.2h～2.5h, 2.1h～2.6h, etc.

In one or more embodiments, multiple batches of glass substrates are heat treated, each batch containing several glass substrates. In the same batch, the density of each glass substrate after heat treatment will be increased compared with that before heat treatment, and its density is much better than that of the glass substrate before heat treatment. Wherein, the density of each glass substrate after heat treatment is increased by 0.15% to 10% and all ranges and sub-ranges therebetween, such as 0.15% to 3%, 0.3% to 6%, 0.2% ～8%, 0.2%～7%, 0.4%～6%, 0.5%～9%, 0.3%～8%, 5%～8%, 2%～5%, 7%～10%, 8%～9 %Wait.

In one or more embodiments, when multiple batches of glass substrates are heat-treated at the same time, the average density between the batches of glass substrates is controlled to ensure stable quality of the glass substrates. Because the change of density means the change of structure, the change of structure will lead to the change of the stress of the glass substrate. It is necessary to control the average density of multiple batches of glass substrates to achieve the quality control of multiple batches of glass substrates. , so that the quality of glass substrates between multiple batches after heat treatment is more stable. If the average density difference between the two batches of glass substrates is large, reaching more than 0.03 g/cm ³ , then the difference in CT-LD values obtained when the two batches of glass substrates are chemically strengthened larger, resulting in unstable quality of the two batches of glass. Therefore, the average density difference between each batch of glass substrates is controlled within a range not greater than 0.03g/ ^cm3 , including not greater than 0.03g/ ^cm3 and all ranges and subranges therebetween, such as 0.005g /cm ³ -0.03g/cm ³ , 0.006g/cm ³ -0.03g/cm ³ , 0.005g/cm ³ -0.01g/cm ³ , 0.007g/cm ³ -0.02g/cm ³ , 0.005g/cm ³ to 0.01g/cm ³ , 0.005g/cm ^{3 , 0.006g/cm 3 , 0.007g/cm 3 , 0.008g/cm 3 , 0.009g/cm 3 , 0.01g/cm 3 , 0.02g /} cm ³ , etc. .

In one or more embodiments, step 2) can be performed before or after 2D hot bending, before or after 2.5D hot bending, or before or after 3D hot bending After hot bending. The sequence of the hot bending process and the heat treatment of the present invention has a certain influence on the effect achieved by the heat treatment of the present invention, because the hot bending process will adversely affect the density of the glass substrate, even if the preparation method of the present invention is used. The density of the glass substrate is increased. If the hot bending process is performed after the preparation method of the present invention, the high density of the glass substrate will decrease, thereby affecting the effect of subsequent chemical strengthening. Therefore, it is preferable to perform the above-mentioned heat treatment on the glass material after the 3D hot bending to achieve the best effect, which can maximize the density of the glass material. When the preparation method of the present invention is adopted, the hot bending process can be performed after preheating in the prior art, and then the heat treatment process of the present invention can be performed, and the preheating treatment in the prior art can be directly omitted.

3. A glass material with high density

At present, the ultra-thin glass used for glass cover plates is produced by the overflow method and the float method. During the production process, it will be annealed to eliminate the internal stress of the glass, so that the glass will not be broken in the subsequent cutting process. . However, the annealing time is often very short, which makes the obtained glass less dense, and the stress effect generated by the subsequent ion exchange will also decrease, resulting in a decrease in the performance of the final strengthened glass, and it will also make the size of the strengthened glass difficult to control and fluctuate. larger. After the glass cover is subjected to 3D hot bending, it is subjected to high temperature hot pressing at 700 ° C ~ 800 ° C. This operation will further deteriorate the internal density of the glass, and the density will decrease. Even if the same strengthening process is used, its stress state is relative to 2.5. The D glass has a 10% to 20% decrease, which makes the mechanical strength of the 3D glass decrease after strengthening.

Before the glass is chemically strengthened for the first time, heat treatment is carried out, which is the preheating treatment in the prior art. The purpose of this preheating is to dry the moisture of the glass and preheat the glass to generate a certain preparatory temperature. Generally, it is only 200℃～350℃, and the heating time is up to 30min, so that there is a thermal transition before the glass enters the salt bath furnace, and there will not be too much temperature change, which will cause the glass to break. The heat treatment of the present invention not only includes the functions of drying moisture and thermal transition, but also enables the glass to be heat-treated within the temperature range of the present invention, the compactness of the glass is further improved, and the sodium-lithium ion exchange efficiency is further improved. The range will be much higher than the 200 ℃ ~ 350 ℃ in the current conventional preheating process.

The difference between the heat treatment process of the present invention and the existing preheating treatment process is that the heat treatment process of the present invention brings great improvement to the physical and chemical properties of the glass. Specifically, in the present invention, the glass material is heat treated at different temperatures, and the Raman test is performed on the glass material before and after the heat treatment to obtain a Raman spectrum, and then the chemical strengthening treatment is performed, and the performance test is performed on the finally obtained glass. It was found that some glasses had excellent drop resistance, while others did not. When analyzing these two glasses with obvious differences in performance, it was found that the Raman test spectra of these glasses had some changes. The Raman spectra were actually composed of multiple frequency peaks. Each peak is analyzed, so it is necessary to perform peak separation processing. Peak splitting method:

1: It is preferred to import the raw data of the Raman spectrum test into the origin8.5 data processing software to draw graphics;

2: Process the data. The processing steps are as follows Analysis, Peak and Baseline, Peakanalyzer, Open Dialog;

3: Select Subtract Baseline in the pop-up window, select Analysis, Peak and Baseline, Multiple Peak Fit, Open Dialog, at the step "Multiple Peak Fit", the origin8.5 data processing software will automatically generate the X of the Raman spectrum peaks axis, as shown by arrow A in Figure 1-4;

4: Next, find the peak intensity separately, select Analysis, Mathematics, Integrate, Open Dialog, and calculate the ID/IG ratio (the intensity ratio of D-peak and G-peak).

After peak separation processing, there are multiple characteristic frequency peaks on the Raman test spectrum, which are 320Hz, 400Hz, 480Hz, 580Hz, 980Hz, 1060Hz, and the cross-sectional area of each characteristic frequency peak is the peak area of the characteristic frequency peak. S. Among them, the calculation method of the peak area is illustrated by taking the peak area S ₉₈₀ of the characteristic frequency peak obtained at the characteristic frequency 980 as an example. A sub-peak is formed at the characteristic frequency 980, and it is confirmed that the peak is around the characteristic frequency 980 (less than the characteristic frequency 980). and greater than the characteristic frequency 980) the intersection of the curve and the X-axis, the area enclosed by the curve connecting the two intersections and the X-axis is calculated as the peak area S ₉₈₀ , specifically to determine the two intersections as the upper and lower limits, expressed in the curve Formula to find the integral. Similarly, the peak area S ₁₀₆₀ of the characteristic frequency peak obtained at the characteristic frequency of 1060 Hz is also obtained by the above calculation method. In Figures 1 to 4, 1 refers to the 980 Hz characteristic frequency peak on the Raman test spectrum, and 2 refers to the 1060 Hz characteristic frequency peak on the Raman test spectrum. After studying the attached drawings _1-4 , it was found that some of the characteristic frequency peaks of some glass materials changed before and after heat treatment. The peak area of the characteristic frequency peak obtained at the frequency of 1060 Hz is S ₁₀₆₀ , and the ratio of the two is M=S ₉₈₀ /S ₁₀₆₀ . Moreover, the peak intensity of the characteristic frequency peak obtained at the characteristic frequency of 480 in the figure is the N value. The N value of these glass materials has changed before and after the heat treatment. decreased by 5% to 15%.

After in-depth research on the glass materials that have undergone the above heat treatment, it is found that the M value of the glass material decreases after heat treatment because the change of S ₉₈₀ before and after heat treatment is not obvious, but the S ₁₀₆₀ has a very obvious increase, which also shows that the glass substrate After heat treatment, the network structure has changed to a certain extent. The six-membered ring layered structure in the network structure of the glass material after heat treatment has increased significantly, and the number of non-bridging oxygen bonds in the six-membered ring layered structure has been significantly increased. At the same time, the decrease of N value indicates that the number of bridging oxygen bonds in the six-membered ring layered structure has decreased. This series of changes indicates that after heat treatment, the network structure of the glass material tends to a more stable six-membered ring layer. Compared with before heat treatment, this structure is more complete, and the density is increased by more than 0.15%, so that the structure of the obtained glass material is more dense, and a glass material with high density is obtained. This high density and these changes on the Raman spectrum are also clearly reflected in the properties of the glass material. The glass material CT-LD _max after the heat treatment of the present invention has a significant change, and the glass obtained after the heat treatment The material CT-LD _max should be at least above 40000MPa/mm, and this series of advantageous changes will also have a positive impact on the subsequent chemical strengthening of the glass material.

To sum up, the heat treatment process of the present invention not only achieves the effect of drying moisture and thermal transition, but also changes the network structure of the glass. positive effects on subsequent chemical strengthening.

After analyzing the processing technology of these glass materials with changed M and N values, it is found that the heat treatment temperature of these glass materials is different from the preheating treatment. These glass materials are obtained after the glass substrate is heat treated before the first chemical strengthening. And, the heat treatment temperature T _heat and the strain point T of the glass material _should have the following relationship:

T _heat =(T _{should be} -70℃)～(T _{should be} +20℃), T _{should be} ≤550℃.

The high-density glass material of the present invention can be obtained through the above treatment process, and the high-density glass material is superior to the non-high-density glass material in all properties, especially when chemical ion exchange is performed. During the research, it was found that in the subsequent chemical ion exchange process of the glass material with high density, Na ⁺ -Li ⁺ exchange was mainly carried out, and the Na ⁺ -Li ⁺ exchange rate was lower than that of the glass sample without the heat treatment of the present invention, The density of the glass material with high density increases and the interior is more compact, which reduces the exchange space for ions to enter during the ion exchange process, and at the same time, the difficulty of entering the exchange ions increases, the rate of ion exchange decreases, and the entire ion exchange process is more difficult. Therefore, it is more difficult for glass materials with high density to ion exchange, so it is speculated that this may lead to poor strengthening effect of glass after ion exchange. However, after research, it is found that under the same exchange time, the glass material with high density of the present invention unexpectedly shows a more excellent side, and the glass material with high density can be exchanged with lower sodium ions. , obtained a higher CT-LD _max than the glass sample without the heat treatment of the present invention, showing the advantage of a dense glass material having a higher strengthening efficiency, these phenomena indicate that the heat treatment process of the present invention is to make the glass network structure more efficient. Dense, the silicon-oxygen tetrahedron in the network structure is more complete and more numerous, and it can also effectively reduce the stress relaxation phenomenon of the glass material during the ion exchange process. The interior of the glass material of the present invention is denser and more stable, and the strengthening efficiency is higher in the whole ion exchange process. This better density and stability are reflected in the performance of the glass material after chemical strengthening. The size change is small, that is, the profile deformation of the strengthened glass material is smaller, the product appearance quality is better, and the drop resistance height of the strengthened glass material is significantly improved, so that its performance, size and profile change. In a stable state, the final chemically strengthened glass material has high drop resistance.

A glass material with high density can be obtained by the preparation method of the present invention, and the CT-LD _max of the glass material after the heat treatment of the present invention is improved to a certain extent, and its CT-LD _max can be at least 40000MPa /mm or more. In one or more embodiments, the CT-LD _max of the glass material after heat treatment is at least 40000MPa/mm or more, preferably 40000MPa/mm～42000MPa/mm, preferably 41000MPa/mm～42000MPa/mm, preferably 42000MPa/mm mm～43000MPa/mm, preferably 43000MPa/mm～44000MPa/mm, preferably 44000MPa/mm～45000MPa/mm, preferably 45000MPa/mm～46000MPa/mm, preferably 46000MPa/mm～47000MPa/mm, preferably 47000MPa/ mm～48000MPa/mm, preferably 48000MPa/mm～50000MPa/mm, preferably 48000MPa/mm～51000MPa/mm, preferably 49000MPa/mm～52000MPa/mm, preferably 51000MPa/mm～52000MPa/mm, preferably 50000MPa/mm mm～53000MPa/mm.

When the general Li-Al-Si glass is subjected to the chemical strengthening limit experiment, the reason for the decrease in stress is that the glass will always have a structural relaxation effect at high temperature, and when the ion exchange reaches the later stage, the exchange increase decreases due to the accumulation of ions inside the glass. The stress from ion exchange is getting lower and lower. When the stress generated by ion exchange cannot compensate for the decrease in stress caused by structural relaxation, the stress inside the glass will tend to decrease. That is to say, the CT-LD has a parabolic trend with the strengthening time, and a maximum stress value, namely CT-LD _max , will be generated at that time. Thereafter, as the strengthening time increases, the increase in the ion exchange amount on the contrary impairs the strengthening properties of the glass. However, when the glass material after the heat treatment is chemically strengthened, it can obtain a higher CT-LD _max with a lower ion exchange amount than the glass sample without the heat treatment of the present invention, thereby improving the strengthening performance of the glass. This will be further described below with respect to the enhancement efficiency of sodium-lithium ions. When the heat-treated glass material is chemically strengthened, the strengthening efficiency is that under the condition that the unit exchange area of the glass is 25 cm ² , the sodium-lithium ion strengthening efficiency of the glass is at least 31000 MPa/mm*g or more. The sodium-lithium ion strengthening efficiency refers to the ratio of CT-LD _max to sodium ion exchange capacity when the glass is subjected to a chemical strengthening limit test to reach CT-LD _max . The calculation of the sodium ion exchange capacity is as follows: m/0.695=sodium ion exchange capacity, where m is the mass increase of the glass due to ion exchange when the glass chemical strengthening limit experiment reaches CT-LD _max , 0.695=( atomic mass - atomic mass of lithium ions) / atomic mass of sodium ions. The higher the sodium-lithium ion strengthening efficiency of the present invention shows that the glass has less sodium ion exchange during the ion exchange process, but the obtained CT-LD _max is high, that is, the highest possible CT can be obtained with as little sodium ion exchange as possible. _-LDmax . The glass material after the heat treatment of the present invention has high compactness, which will alleviate the structural relaxation effect of the glass at high temperature, so that the exchange amount of sodium ions can have a beneficial effect on the stress effect of the glass, because once chemically strengthened When the time exceeds the time when the CT-LD of the glass reaches the maximum value, the amount of sodium ion exchange after that cannot compensate for the stress drop caused by the structural relaxation, which has no beneficial effect on the glass stress effect, but will start to have a negative impact. Therefore, in one or more embodiments, when the glass material after the heat treatment is chemically strengthened, its strengthening efficiency is at least 31000MPa/mm*g or more, preferably 31000MPa/mm*g～40000MPa/mm*g , preferably 40000MPa/mm*g～50000MPa/mm*g, preferably 31000MPa/mm*g～35000MPa/mm*g, preferably 32000MPa/mm*g～36000MPa/mm*g, preferably 32000MPa/mm*g ～38000MPa/mm*g, preferably 35000MPa/mm*g～39000MPa/mm*g, preferably 40000MPa/mm*g～45000MPa/mm*g, preferably 41000MPa/mm*g～48000MPa/mm*g, preferably 42000MPa/mm*g～49000MPa/mm*g, preferably 45000MPa/mm*g～48000MPa/mm*g, preferably 45000MPa/mm*g～51000MPa/mm*g, preferably 50000MPa/mm*g～55000MPa /mm*g.

In the existing chemical strengthening process, the smaller the ion exchange amount, the smaller the CT-LD value of the strengthened glass material. However, the glass network structure processed by the preparation method of the present invention is more dense, and the silicon-oxygen tetrahedron structure of the network structure is more complete and the number is more, which also makes in the subsequent chemical strengthening process, and has not undergone the present invention. Compared with the heat-treated glass, the glass heat-treated by the method of the present invention can obtain a higher CT-LD with a lower sodium ion exchange amount, so that the ion exchange rate is small but the CT-LD obtained per unit exchange amount can be obtained. larger, which indicates that the heat treatment process of the present invention can effectively improve the strengthening efficiency of glass ion exchange. In one or more embodiments, when the glass material after the heat treatment is chemically strengthened, its sodium-lithium ion strengthening efficiency is improved compared with the glass material that has not undergone the heat treatment according to the present invention. The amplitude is at least 5000MPa/mm*g or more, preferably 7000MPa/mm*g or more, preferably 5000MPa/mm*g～6000MPa/mm*g, preferably 5500MPa/mm*g～6500MPa/mm*g, preferably 6000MPa /mm*g～7000MPa/mm*g, preferably 6500MPa/mm*g～7000MPa/mm*g, preferably 7000MPa/mm*g～10000MPa/mm*g, preferably 7500MPa/mm*g～8000MPa/mm *g, preferably 8000MPa/mm*g～10000MPa/mm*g, preferably 8000MPa/mm*g～9000MPa/mm*g, preferably 9000MPa/mm*g～10000MPa/mm*g.

The improvement of the sodium-lithium ion strengthening efficiency makes the glass material only need to exchange less sodium ions under the condition of obtaining the same stress state and the same CT-LD. In this case, the sodium ions exchanged out of the salt bath will have less lithium ions. The heat treatment method of the present invention can control the exchange amount of sodium and lithium ions to a certain extent under the same stress state, so as to avoid the glass after heat treatment. Excessive lithium ions or other ions in the ion exchange with sodium ions, resulting in the poisoning of the salt bath. Salt bath poisoning means that after the ion exchange in the salt bath, the lithium ions in the glass will enter the salt bath, so that the concentration of lithium ions in the salt bath increases, while the ion concentration of the salt bath itself participating in ion exchange decreases, resulting in the salt bath. The difference in ion concentration for ion exchange with the glass is reduced, making it more difficult for the lithium ions in the glass to be exchanged out. To solve this problem, it is necessary to replace the salt bath, replacing the poisoned salt bath with a new one. However, this operation will greatly reduce the use of the salt bath, that is, the salt bath needs to be replaced after a few ion exchanges, which will lead to an increase in the amount of the salt bath and increase the production cost. Therefore, under the premise of obtaining the same stress state, the amount of sodium ions to be exchanged is reduced, so that the amount of lithium ions exchanged by sodium ions is also reduced, so that the salt bath can only be replaced after multiple ion exchanges. To extend the service life of the salt bath, reduce the amount of the salt bath, and control the production cost within a certain range.

In one or more embodiments, the ratio M of the peak area S ₉₈₀ of the characteristic frequency peak obtained at the characteristic frequency 980 Hz on the Raman test spectrum to the peak area S ₁₀₆₀ of the characteristic frequency peak obtained at the characteristic frequency 1060 Hz should not exceed high. Because the increase of the M value indicates that the peak area S ₁₀₆₀ of the characteristic frequency peak obtained at the characteristic frequency 1060 Hz is too small, the six-membered ring layered structure in the glass substrate network structure is too small, and the non-bridging oxygen bond in the six-membered ring layered structure is too small If the amount of the glass substrate is too low, the density of the glass substrate will be low, and the compactness will be poor, which will affect the effect of subsequent chemical strengthening of the glass substrate. Controlling the M value should not be too high, that is, it is necessary to increase the number of six-membered ring layered structures in the glass substrate, so the preparation method of the present invention is required to achieve the effect that the M value will not be too high. The M value is not higher than 0.6, including not more than 0.6 and all ranges and sub-ranges therebetween, such as 0.1-0.2, 0.15-0.25, 0.1-0.3, 0.2-0.35, 0.1-0.4, 0.3-0.55, 0.1- 0.5, 0.25~0.5, 0.1~0.55, 0.01~0.25, 0.2~0.3, 0.05~0.35, 0.3~0.4, 0.45~0.55, 0.4~0.55, 0.1, 0.2, 0.3, 0.4, 0.5, 0.55, 0.6, etc. After in-depth research on the glass materials that have undergone the above heat treatment, it is found that the M value of the glass material decreases after heat treatment because the change of S ₉₈₀ before and after heat treatment is not obvious, but the S ₁₀₆₀ has a very obvious increase, which also shows that the glass substrate After heat treatment, the network structure has changed to a certain extent. The six-membered ring layered structure in the network structure of the glass material after heat treatment has increased significantly, and the number of non-bridging oxygen bonds in the six-membered ring layered structure has been significantly increased. At the same time, the decrease of N value indicates that the number of bridging oxygen bonds in the six-membered ring layered structure has decreased. This series of changes indicates that after heat treatment, the network structure of the glass material tends to a more stable six-membered ring layer. like structure.

In one or more embodiments, the M value of the glass material after heat treatment is decreased compared with that before heat treatment, which indicates that after the heat treatment of the present invention, the number of six-membered ring layered structures in the glass material is significantly increased increase, and the number of non-bridging oxygen bonds in the six-membered ring layered structure also increases significantly, so that the network structure of the glass material tends to a more stable six-membered ring layered structure after the heat treatment in the present invention. This structure The above changes are reflected in the performance of the glass material, that is, the change in density, and the density of the glass material has been significantly improved. Therefore, the M value of the glass material after heat treatment is reduced by 3% to 10% and all ranges and sub-ranges therebetween, such as 3% to 5%, 3% to 6%, 3% to 7%, 3 %～8%, 3%～9%, 4%～5%, 4%～6%, 6%～7%, 4%～8%, 7%～8%, 6%～10%, 5%～ 6%, 5% to 7%, 5% to 8%, 7% to 9%, 9% to 10%, etc. At the same time, the decrease of N value indicates that the number of bridging oxygen bonds in the six-membered ring layered structure has decreased.

In one or more embodiments, the N value of the glass material decreases significantly after heat treatment compared with before heat treatment, which is due to the decrease in the number of bridging oxygen bonds in the six-membered ring layered structure, and the bridging oxygen bonds It is the oxygen ion in the glass network as the common vertex of the two network-forming polyhedra, which indicates that the glass material network structure has formed a more stable six-membered ring layered structure after heat treatment. Therefore, the N value of the glass material after heat treatment is reduced by 5% to 15% and all ranges and sub-ranges therebetween, such as 5% to 6%, 5% to 8%, 5% to 7%, 6% %～8%, 5%～9%, 5%～15%, 5%～11%, 6%～10%, 5%～12%, 7%～8%, 6%～10%, 6%～ 13%, 7% to 10%, 8% to 13%, 9% to 15%, 9% to 14%, etc.

In one or more embodiments, the strain point T of the glass material _should be less than or equal to 550°C, less than or equal to 540°C, less than or equal to 530°C, less than or equal to 520°C, less than or equal to 510°C, less than or equal to 500℃, less than or equal to 490℃, less than or equal to 480℃, less than or equal to 470℃, less than or equal to 460℃, less than or equal to 450℃, less than or equal to 440℃, less than or equal to 430℃, less than or equal to 420℃ , less than or equal to 410°C, less than or equal to 400°C, less than or equal to 390°C, less than or equal to 380°C, and the minimum is 370°C.

After the heat treatment at the heat treatment temperature of the present invention, the CT-LD _max of the glass material is greatly improved. In one or more embodiments, the CT-LD _max of the glass material after the heat treatment is increased compared with that before the heat treatment. 8% to 30% and all ranges and subranges therebetween, such as 8% to 20%, 11% to 22%, 10% to 20%, 8% to 25%, 13% to 20%, 14% to 22% %, 10% to 27%, 11% to 28%, 8% to 26%, 14% to 29%, 11% to 25%, 15% to 29%, 15% to 30%, 16% to 29%, 17% to 28%, etc.

In one or more embodiments, since the number of six-membered ring layered structures in the glass material is increased to a certain extent after heat treatment, the density of the glass material after heat treatment also changes significantly, so that the glass material becomes more dense. The density of the glass material after heat treatment is increased by 0.15% to 10% and all ranges and sub-ranges therebetween, such as 0.15% to 3%, 0.3% to 6%, 0.2% to 8%, 0.2% to 7%, 0.4% to 6%, 0.5% to 9%, 0.3% to 8%, 5% to 8%, 2% to 5%, 7% to 10%, 8% to 9%, etc.

In one or more embodiments, the glass substrate can be ultra-thin glass-ceramic prepared by float method or overflow method, and the thickness of the glass substrate includes 0.3 mm to 1.5 mm and all ranges and sub-ranges therebetween, 0.4mm～1.0mm, 0.5mm～1.0mm, 0.6mm～1.2mm, 0.7mm～1.3mm, 0.7mm～1.4mm, 0.5mm～1.3mm, 0.8mm～1.0mm, 0.6mm～1.4mm, 0.9mm ~1.2mm, 0.8mm~1.5mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

4. A chemically strengthened glass and its preparation method

The invention also discloses a preparation method of chemically strengthened glass, which comprises: performing primary ion exchange or secondary ion exchange on the glass material with high density of the invention using a nitrate bath containing sodium ions or sodium ions and potassium ions.

In one or more embodiments, the salt bath of the primary ion exchange and the secondary ion exchange can be selected from a salt bath containing sodium ions, or can be selected from a mixed nitrate salt bath containing sodium ions and potassium ions. By placing the ion-exchangeable glass in a molten bath containing cations (eg K ⁺ , Na ⁺ , etc.) and allowing the cations of the molten bath to diffuse into the glass, while the glass's smaller alkali metal ions (eg Na ⁺ , Li ⁺ ) diffuse out from the glass and enter into the molten bath for chemical strengthening of the base glass. Replacing smaller cations with larger cations created compressive stress near the top surface of the glass. Tensile stress is created in the interior of the glass to balance the compressive stress near the surface. For ion exchange processes, they can independently be thermal diffusion processes or electronic diffusion processes. The glass is immersed in one or more ion exchange baths, and an ion exchange process with washing and/or annealing steps between each immersion. Of these, nitrates are conventional as salts to be used for ion exchange, but any suitable salt or combination of salts may also be used. For example, the salt bath may contain at least one of _KNO3 and NaNO3, and the salt bath may contain 100% _KNO3 , 100 _% NaNO3, or a combination _{of KNO3} and _NaNO3 . _KNO3 (compared to NaNO3 ₎ contains larger alkali metal ions (ie, K ⁺ ), which can more easily exchange medium-sized alkali metal ions (eg, Na ⁺ ) in the glass. Similarly, NaNO ₃ (when compared to KNO ₃ ) contains medium-sized alkali metal ions (ie, Na ⁺ ), which can more easily exchange smaller metal ions (eg, Li ⁺ ) in the glass. The high-density glass material obtained in the step 2) can be used for a primary ion exchange reaction or a secondary ion exchange reaction. The high-density glass material of the present invention is put into a high-temperature salt bath for one-time ion exchange, wherein the temperature of the salt bath is maintained between 400°C and 700°C. Similarly, a secondary ion exchange reaction can also be performed, and the glass material with high density is placed in two high-temperature salt baths twice for the ion exchange reaction, wherein the temperature of the two salt baths can be controlled at 400℃～700℃ between °C. Regardless of whether the glass material after the heat treatment of the present invention selects primary ion exchange or secondary ion exchange, during the ion exchange process, due to the high density of the glass material, the stress relaxation phenomenon of the glass material during ion exchange can be reduced. The performance, strengthening size and profile changes of the glass material are kept in a stable state during the whole ion exchange process, so as to obtain glass products with better performance.

The present invention also discloses the chemically strengthened glass prepared according to the above preparation method.

5. Electronic terminals as consumer goods

The invention also discloses a consumer electronic terminal. The consumer electronic terminal includes a casing and an electronic component, and the electronic component is partially located in the casing. The housing includes a front surface, a rear surface and a side surface; the electronic assembly includes a display located at or adjacent to the front surface of the housing; the front or/and rear or/and side surfaces include chemically strengthened glass. Consumer electronic terminals include mobile phones, tablet computers or other electronic terminals.

The chemically strengthened glass of the present invention may be included in other articles, such as articles with displays (or display articles) (eg, consumer electronics including mobile phones, tablets, computers, navigation systems, etc.), construction articles, transportation articles (eg, automobiles, trains, airplanes, marine vehicles, etc.), appliance articles, or any article requiring a certain degree of clarity, scratch resistance, abrasion resistance, or a combination thereof.

In some embodiments, a cover article may also be included overlying the front surface of the housing or on the display, the cover article and/or a portion of the housing comprising the chemically strengthened glass of the present invention.

6. Materials with high density glass materials

The present invention also provides a glass material with high density; specifically, based on the mole % of oxides, the glass material basically contains 8 mol % or more of Al ₂ O ₃ and 60 mol % to 70 mol % of SiO ₂ , and must contain more than 6 mol% Li ₂ O.

In the composition of the glass material of the present invention, the glass network components are mainly SiO ₂ and Al ₂ O ₃ , both of which can improve the strength of the glass network structure, and the high network structure composition can increase the amount of oxygen in the glass bridge, especially The content of the silicon component can improve the strength of the network structure of the glass. While Al ₂ O ₃ helps to increase the rigidity of the glass network, Al ₂ O ₃ can exist in the glass in a tetra- or penta-coordination, which increases the bulk density of the glass network and thus increases the compressive stress formed by chemical strengthening . High network structure strength plays an important role in the ion exchange of glass, because during the ion exchange process, the glass will undergo K ⁺ -Na ⁺ , Na ⁺ -Li ⁺ binary ion exchange step by step or simultaneously to form a composite compressive stress Floor. However, in this process, the glass will have a stress relaxation effect due to the exchange of ions of different radii, and the high temperature and long reaction time in the ion exchange reaction will weaken the composite compressive stress layer, especially the middle and deep layers. , but the content of SiO ₂ and Al ₂ O ₃ is not easy to be too high, too high will lead to the increase of the melting temperature of the glass material and the temperature of the strain point, so the amount of SiO ₂ +Al ₂ O ₃ should be controlled at a reasonable Within the range, it can not only ensure the compactness of the network structure of the glass material, thereby ensuring the strength of the network structure of the glass material, but also reduce the difficulty of melting the glass material, so that the glass material can obtain a lower strain point. In some embodiments, SiO ₂ +Al ₂ O ₃ in the glass material is not greater than 82 mol%, including 70 mol% to 80 mol% and all ranges and subranges therebetween, such as 70 mol% to 75 mol%, 71 mol% to 74 mol%, 70mol%～76mol%, 72mol%～80mol%, 74mol%～80mol%, 75mol%～80mol%, 76mol%～80mol%, 77mol%～80mol%, 72mol%～77mol%, etc.

Li ₂ O is also the main component of ion exchange. The molar proportion of Li ₂ O is greater than 6 mol%, preferably controlled within the range of 6 mol% to 10 mol%. The radius of Na ⁺ in the ion exchange salt bath is smaller than that of K ⁺ , which makes it more Go deep inside the glass to carry out ion exchange with Li ⁺ , Li ⁺ in the glass is the key exchange ion to form deep compressive stress, and carry out Na ⁺ -Li ⁺ exchange with Na ⁺ in the ion exchange salt bath, so that the glass can form high depth pressure. stress layer. In some embodiments, the glass may include 6-10 mol% _Li2O and all ranges and subranges therebetween, eg, 7-10 mol%, 7.8-10 mol%, 7.5-10 mol%, 8.6 mol%～10mol%, 8.2mol%～10mol%, 9.1mol%～10mol%, 9.2mol%～10mol%, 8.5mol%～9.5mol%, 9.5mol%～10mol%, 7.7mol%～9.8mol%, 7.5 mol %, 8 mol %, 9 mol %, 7.8 mol %, 8.6 mol %, 9.5 mol %, or 10 mol %.

Since Na ₂ O and Li ₂ O are alkali metal oxides, they are free in the glass, and the amount of sodium oxide is less than that of lithium oxide, which is beneficial to the Na ⁺ -Li ⁺ exchange degree of the glass material and improves the deep pressure stress, but the excess oxygen ions will break the bridge oxygen and break the network structure, resulting in a decrease in the intrinsic strength of the glass material and a decrease in the stress threshold that can be safely accommodated. Therefore, it is necessary to control the mole ratio of Na ₂ O and Li ₂ O, and Na ₂ The molar ratio of O and Li ₂ O includes less than 15 mol % Na ₂ O + Li ₂ O and all ranges and subranges therebetween, eg, 8 mol% to 11 mol %, 6 mol % to 12 mol %, 5 mol % to 10.5 mol % , 4mol%～10.7mol%, 8mol%～13mol%, 7mol%～12.5mol%, 7mol%～14.5mol%, 9mol%～12mol%, 7mol%～10.9mol%, 5.6mol%～14.8mol%, 9mol% %～13.4mol%, 7mol%～12.8mol%, 7mol%～13.4mol%, 4mol%～10.8mol%, 4mol%, 5mol%, 6.2mol%, 7.4mol%, 8.6mol%, 9.8mol%, 11mol% %, 12 mol %, 13 mol %, 14.5 mol %, or 14 mol %.

The composition of the glass material of the present invention also includes K ₂ O, the molar proportion of K ₂ O is controlled between 0 mol% and 5 mol %, and K ₂ O is the main component of ion exchange. In some embodiments, the glass may include 0-5 mol _% K2O and all ranges and subranges therebetween, eg, 0.2-2 mol%, 0.3-4.8 mol%, 0.1-3.6 mol% %, 2.3mol%～4mol%, 1.4mol%～3.8mol%, 1.5mol%～4mol%, 1mol%～3.5mol%, 1mol%～3mol%, 1mol%～3.8mol%, 1mol%～2.5mol% , 1mol%～4.2mol%, 0mol%, 1mol%, 2.5mol%, 1.5mol%, 2mol%, 2.5mol%, 4mol%, 2.7mol%, 2.9mol%, 2.1mol%, 3mol%, 3.6mol% , 3.5mol%, 3.4mol%, 3.3mol%, 3.2mol%, 3.1mol%, or 5mol%.

The composition of the glass material of the present invention also includes B ₂ O ₃ and B ₂ O ₃ as the secondary network structure of the glass. An appropriate amount of B ₂ O ₃ can promote the melting of the glass at high temperature, reduce the difficulty of melting, and can effectively increase the concentration of the glass in the glass. The rate of ion exchange, especially the exchange capacity of K ⁺ -Na ⁺ is greatly improved, but excessive B ₂ O ₃ will lead to the weakening of the glass network structure, so it is necessary to control the amount _of B ₂ O _{3 added} . The molar ratio is controlled within a range of not more than 3 mol%. In some embodiments, the glass may include no greater _{than 3} mol% B2O3 and all ranges and subranges therebetween, such as 0-2.8 mol%, 0-2.5 mol%, 0-2.3 mol%, 0-1.5 mol%, 0～1.7mol%, 1.1mol%～2.4mol%, 1mol%～2.5mol%, 0mol%～1.0mol%, 1.2mol%～2.3mol%, 1.5mol%～3.0mol%, 0mol%, 1.5mol%, 1.8mol%, 2.0mol%, 2.3mol%, 2.4mol%, 2.6mol%, 2.7mol%, 2.8mol%, 0.5mol%, 0.7mol%, 0.3mol%, 0.2mol%, 0.1mol% %, 0.6 mol%, or 3.0 mol%. _In one or more alternative embodiments, the glasses of the present invention may be substantially free _of B2O3.

The composition of the glass material of the present invention also includes MgO, and the molar proportion of MgO is controlled between 2 mol% and 7 mol%. As an intermediate of the glass network structure, MgO can reduce the high temperature viscosity of the glass, thereby increasing the Young's modulus of the glass. effect. In some embodiments, the glass may include 2 mol% to 7 mol% MgO and all ranges and subranges therebetween, eg, 3.5 mol% to 6.8 mol%, 2.5 mol% to 6.6 mol%, 3.6 mol% to 5.2 mol% , 3.4mol%～5.8mol%, 3.5mol%～4.0mol%, 3mol%～4.5mol%, 2.7mol%～6.8mol%, 3.5mol%～6.0mol%, 3.0mol%～6.5mol%, 4mol% ~4.5mol%, 3.5mol%, 4.5mol%, 2.8mol%, 4mol%, 4.5mol%, 3.8mol%, 2.6mol%, 5.5mol%, 2.5mol%, 5.8mol%, 5.6mol%, 4.2mol% %, 4.4 mol%, 4.3 mol%, 6.2 mol%, or 6.1 mol%.

In one or more embodiments, ZrO ₂ may be included in the formulation of the glass material of the present invention. ZrO ₂ can improve the toughness of the glass, but excessive ZrO ₂ will cause the glass to crystallize and reduce the devitrification resistance. In these embodiments, ZrO may be less than ₁ mol%, less than 0.9 mol%, less than 0.8 mol%, less than 0.7 mol%, less than 0.6 mol%, less than 0.5 mol%, less than 0.4 mol%, less than 0.3 mol%, less than 0.2 mol% mol%, amounts less than 0.1 mol%, and all ranges and subranges therebetween are present. In one or more alternative embodiments, the glasses of the present invention may be substantially free of _ZrO2 .

In one or more embodiments, CaO may be included in the formulation of the glass material of the present invention. In these embodiments, the CaO may be less than or equal to 2 mol%, less than or equal to 1.9 mol%, less than or equal to 1.8 mol%, less than or equal to 1.7 mol%, less than or equal to 1.6 mol%, less than or equal to 1.5 mol%, less than or equal to 1.5 mol% It is present in amounts of 1.4 mol% or less, 1.3 mol% or less, 1.2 mol% or less, 1.1 mol% or less, 1.0 mol% or less, and all ranges and subranges therebetween. In one or more alternative embodiments, the glasses of the present invention may be substantially free of CaO.

The present invention will be described below through specific embodiments.

The present invention provides a method for preparing a glass material with high density. Taking Example 1-1 as an example, the method includes the following steps:

1) First, accurately weigh the raw materials according to the ratio of the raw materials in the recipe 1 in Table 1, and then fully mix the raw materials to prepare a glass substrate plate with a thickness of 0.7 mm by the overflow method or the float method;

2) The glass substrate plate obtained in step 1) is heat-treated before its first chemical strengthening, wherein the heat-treatment temperature is 537° C. and the heat-treatment time is 2h, to obtain the glass material Example 1-1 with high density.

Table 1 is the recipe of different embodiments of glass in the present invention

Composition and mole percent		Material 1	Material 2	recipe 3	recipe 4	recipe 5
SiO2	69	70	65	64.5	62
Al 2 O 3	10	10	11.5	10	13
B 2 O 3	1.5	--	2	3	2
MgO	3	4	3	4.5	4
CaO	--	--	--	1	2
ZrO 2	0.5	0.5	0.5	--	0.5
Na 2 O	6	4	5	7	4.5
K 2 O	2	1.5	4	3	3
Li 2 O	8	10	9	7	9

Note: "--" means that the glass does not contain this component.

Table 2 is the glass heat treatment process parameters and properties of the present invention

Table 3 shows the changes of glass material density and CT-LD at different heat treatment temperatures

Note: The heat treatment time in Table 3 is all 2h.

Table 4 shows the changes of glass material density and CT-LD after different heat treatment processes

Note: Table 4 adopts the heat treatment method combining the preheat treatment process + the heat treatment process of the present invention.

Table 5 is the comparison of N value and M value without heat treatment and after heat treatment

	N value	M value
Example 2-7 without heat treatment	701	0.6237
Embodiment 2-8 heat treatment	648	0.5941
Example 4-7 without heat treatment	142	0.5742
Embodiment 4-8 heat treatment	126	0.5537

Note: In Table 5, the heat treatment temperature of Examples 2-8 and Example 4-8 are both 520°C, and the heat treatment time is 2h.

Table 6 shows the performance comparison of glass materials without heat treatment and after heat treatment after chemical strengthening (sample thickness is 0.7mm)

Table 7 shows the comparison of chemical strengthening of glass materials without heat treatment and after heat treatment (sample thickness is 0.7mm, chemical strengthening conditions: 100% NaNO ₃ *430 ℃, chemical strengthening time is the time to reach the maximum CT-LD)

In Tables 2 to 7, Example 1-1, Example 1-9 and Example 1-10 correspond to recipe 1 in Table 1, Example 2-1, Example 2-2, Example 2-3, Example 2-4, Example 2-5, Example 2-6, Example 2-7, Example 2-8, Example 2-9 and Example 2-10 correspond to recipe 2 in Table 1, and the implementation Example 3-1, Example 3-2, Example 3-3, Example 3-4, Example 3-5 and Example 3-6 correspond to recipe 3 in Table 1, Example 4-1, Example 4-7 and Example 4-8 correspond to recipe 4 in Table 1, and Example 5-1 corresponds to recipe 5 in Table 1.

It can be seen from Table 2 that the density of the glass of the present invention after heat treatment in Example 1-1, Example 2-1, Example 3-1, Example 4-1 and Example 5-1 is as follows: It is greatly improved, and it is also accompanied by the improvement of Vickers hardness and Young's modulus, which shows that after the treatment of the heat treatment process of the present invention, the bond lengths in the silicon-oxygen tetrahedron and the aluminum-oxygen tetrahedron in the glass become shorter, and the overall network of the glass becomes shorter. The structure is more complete and compact, and the resulting glass is stronger.

In the study of the influence of heat treatment temperature on the properties of glass, taking Example 2-2 and Example 3-2 as examples, changing the temperature of heat treatment and testing the conditions of Example 2-2 and Example 3-2 under different heat treatment temperatures , the density of the glass and the variation of CT-LD. From the examples 2-1 and 3-1 in Table 2, it can be known that the glass strain points of the materials 2 and 3 are 516°C and 524°C. The heat treatment temperature range, combined with Table 3, can be seen that when the heat treatment temperature is controlled within the range of (T _{should be} -70°C) ~ (T _{should be} +20°C), the glass of Example 2-2 and Example 3-2 Both the density and CT-LD have been significantly improved, but when the heat treatment temperature is not in the above range, for example, when the heat treatment temperature is 380 °C, the density of the glass changes very little compared to 300 °C and 0 °C, and the change in CT-LD The amplitude is not large, which proves that the too low heat treatment temperature has little contribution to the properties of the glass, and after the heat treatment temperature exceeds 560 °C, the density of the glass decreases, and the CT-LD also increases with the temperature. There is a sharp decline in the rise, which shows that the excessive heat treatment temperature will not only reduce the density of the glass, but also weaken the network structure of the glass and destroy the performance of the glass. Therefore, the heat treatment temperature is closely related to the strain point of the glass, and the glass with high density of the present invention can be obtained only by controlling it within the range of (T _{should be} -70°C) to (T _{should be} +20°C).

The present invention also combines the heat treatment process with the preheat treatment process. See Table 4. All the examples are treated with a combination of two heat treatment processes. The temperature of the treatment is controlled between 200°C and 350°C. As shown in Table 4, for example, in Example 3-6, after preheating at 300°C and then performing the heat treatment process at 520°C in the present invention, compared with only after preheating at 300°C (before heat treatment in the present invention), Both the density and CT-LD _max of the glass material showed a very significant increase, which indicates that the combination of preheating and heat treatment can achieve the effect of increasing the density of the glass. As can be seen from Table 3, Example 3-2 was only heat-treated at 300 °C, and the density of the glass material did not change before and after the heat treatment. Therefore, it can be determined that the increase in the density of the glass material in Example 3-6 was mainly due to the increase in the density of the glass material at 520 °C. ℃ heat treatment, the preheating process at 300 ℃ will not affect the structure of the glass, nor will it affect the technical effect of the heat treatment process of the present invention. The combination of the two processes can also achieve the effect of increasing the glass density. Also, this also confirms that the presence or absence of the preheating process has no effect on the density of the glass, that is, it does not bring optimization of the network structure to the glass, but only plays the role of drying moisture and thermal transition.

As shown in Tables 5 and 6, the effect of the heat treatment process of the present invention on the glass is not limited to density and tensile stress, but also affects the chemical strengthening of the glass, especially when chemical ion exchange is performed. For example, comparing Example 2-7 with Example 2-8 and Example 4-7 with Example 4-8, the N value and M value of the sample without heat treatment after heat treatment, its N value and The value of M showed a relatively large decline. Combined with Figures 1 to 4, the decrease of the M value indicates that in the heat-treated sample structure, the peak area S ₁₀₆₀ of the characteristic frequency peak obtained at the characteristic frequency 1060 has a relatively large increase, which indicates that the heat-treated sample structure has six The number of membered ring layered structures has increased significantly, and the number of non-bridging oxygen bonds in the six-membered ring layered structure has been significantly increased. The number has decreased and the bond length has become shorter. This series of changes indicates that after heat treatment, the network structure of the glass material tends to be a complete six-membered ring layered structure, and this structure is more complete than before heat treatment. The resulting glass material has a denser structure, and this series of advantageous changes will also have a positive impact on the subsequent chemical strengthening of the glass material.

In Table 7, the exchange amount g of sodium ions is normalized to the exchange amount g of sodium ions when the mass of the glass sample is 100 g. Under the same thickness, the greater the mass, the greater the sodium ion exchange capacity of the sample. In general production, the quality of the product is different, but the obtained stress has nothing to do with the quality. In order to better and correctly compare the ion exchange efficiency and the sodium ion exchange efficiency, in the present invention, no matter how much the sample quality is, the This was converted into 100 g to calculate the sodium ion exchange capacity. As can be seen from Table 7, the sodium ion exchange capacity required for the maximum CT-LD of Examples 1-9 and 2-9 is achieved during the chemical strengthening process without being treated by the method of the present invention. are 1.268g and 1.352g, and the sodium ion exchange amount required to achieve the maximum CT-LD of Examples 1-10 and 2-10 after the preparation method of the present invention is only 1.149g and 1.240g , compared with the examples not treated by the method of the present invention, the sodium ion exchange capacity has a very significant decrease, and the finally obtained CT-LD has a very significant improvement, which shows that after the preparation method of the present invention The network structure of the treated glass is more dense, and the silicon-oxygen tetrahedron structure of the network structure is more complete and more numerous, which can also effectively improve the strengthening efficiency of glass sodium and lithium ion exchange. The improvement of sodium-lithium ion strengthening efficiency reduces the number of sodium ions that need to be exchanged when the glass obtains the same stress state and the same CT-LD, and also reduces the number of lithium ions exchanged into the salt bath. 7 It can be seen that, compared with the glass not treated by the method of the present invention, the amount of lithium ions in the salt bath of the former is slightly higher than that of the latter after chemical strengthening. This also proves that the heat treatment method of the present invention can control the exchange amount of sodium and lithium ions to a certain extent under the same stress state, so as to avoid excessive ion exchange between other ions in the glass and sodium ions after heat treatment. Lead to the poisoning phenomenon of the salt bath, which can also achieve the purpose of prolonging the service life of the salt bath. The glass sample with high density obtained after being processed by the preparation method of the present invention finally shows more excellent performance, and can obtain more excellent performance with a lower sodium ion exchange amount, which is comparable to that without heat treatment. Compared with the sample of the present invention, the glass with high density of the present invention is more dense and stable inside, and can also make its performance, size and profile change in a stable state during the whole ion exchange process, and finally convert these advantages to have High drop resistance.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that those technical solutions of the present invention are modified or equivalently replaced without departing from the present technology. The purpose and scope of the solution should be included in the scope of the claims of the present invention.

Claims (17)

1. A method for preparing a high-density glass material, characterized in that it comprises the following steps:

   1) obtaining a glass substrate containing an alkali metal, wherein the alkali metal at least contains lithium element;

   2) heat-treating the glass substrate obtained in step 1) before its first chemical strengthening to obtain the high-density glass material;

   Wherein, the _heat treatment temperature T and the strain point T of the glass material _{should be} controlled as follows:

   T _heat =(T _{should be} -70℃)～(T _{should be} +20℃);

   The strain point T _{should be} ≤550°C.
2. The method for preparing a glass material with high density according to claim 1, wherein the glass substrate obtained in step 1) is preheated at 200°C to 350°C before step 2).
3. The method for preparing a glass material with high density according to claim 1, wherein the time of the heat treatment in step 2) is 1 h to 12 h.
4. The method for preparing a glass material with high density according to claim 1, wherein the density of the glass substrate after heat treatment is increased by 0.15% to 10% compared with that before the heat treatment.
5. The method for preparing a glass material with high density according to claim 1, wherein the step 2) is performed before or after 2D hot bending; or before or after 2.5D hot bending carried out; or before or after 3D hot bending.
6. A glass material with high density, characterized in that, the glass material with high density is obtained by the method for preparing a glass material with high density according to any one of claims 1 to 5, and after the heat treatment The CT-LD _max of the glass material is at least 40000MPa/mm or more.
7. The glass material with high density according to claim 6, wherein when the glass material after the heat treatment is chemically strengthened, its sodium-lithium ion strengthening efficiency is at least 31000 MPa/mm*g or more.
8. The glass material with high density according to claim 6, characterized in that, when the glass material after the heat treatment is chemically strengthened, its sodium-lithium ion strengthening efficiency is improved by at least 5000 MPa/mm*g or more.
9. The glass material with high density according to claim 6, wherein the glass material with high density satisfies the following conditions:

   The Raman test spectrum is obtained by conducting Raman test on the glass material before and after heat treatment; wherein, the peak area S of the characteristic frequency peak obtained at the characteristic frequency of 980 is ₉₈₀ and the peak area S of the characteristic frequency peak obtained at the characteristic frequency of 1060 The ratio of ₁₀₆₀ is M, and the M value of the glass material after heat treatment is reduced by 3% to 10% compared with that before heat treatment; and the peak intensity of the characteristic frequency peak obtained at the characteristic frequency of 480 in the figure is the N value. The N value decreased by 5% to 15% compared with that before the heat treatment.
10. The glass material with high density according to claim 9, wherein the M value is not higher than 0.6.
11. The glass material with high density according to claim 6, wherein the CT-LD _max of the glass material after the heat treatment is increased by 8% to 30% compared with that before the heat treatment.
12. The glass material with high density according to claim 6, wherein the density of the glass material after the heat treatment is increased by 0.15% to 10% compared with that before the heat treatment.
13. The glass material with high density according to claim 6, wherein the thickness of the glass substrate is 0.3 mm to 1.5 mm.
14. A method for preparing chemically strengthened glass, comprising: using the high-density glass material according to any one of claims 6 to 13 in a nitrate bath containing sodium ions or sodium ions and potassium ions Primary ion exchange or secondary ion exchange.
15. A chemically strengthened glass prepared by the preparation method according to claim 14 .
16. An electronic terminal as a consumer product, characterized in that it includes:

    a housing including a front surface, a rear surface and a side surface;

    and an electronic assembly located partially within the housing, the electronic assembly including a display located at or adjacent to a front surface of the housing;

    the front surface or/and the back surface or/and the side surfaces comprise chemically strengthened glass as claimed in claim 15;

    The electronic terminal as a consumer product includes a mobile phone, a tablet computer, or other electronic terminals.
17. The electronic terminal as a consumer product according to claim 16, wherein,

    Also included is a cover article overlying at the front surface of the housing or on the display, the cover article comprising the chemically strengthened glass of claim 15.

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